Entrainment of the breathing rhythm to that of the rhythm of limb movement during exercise has been shown to decrease oxygen consumption for cycling at a moderate workload. This study examined the effect of entrainment on oxygen consumption during treadmill walking at two workloads. For each workload, 8 subjects performed two exercise protocols consisting of walking on a treadmill for 8 min. For the first protocol they received no instructions, but for the second protocol they were instructed to coordinate one breath per auditory cue which was provided during the last 4 min of exercise. The auditory cue was transmitted as a click via headphones. It was derived from a foot switch and was designed to synchronize breathing to the walking pace at a respiratory frequency close to that observed in the first protocol. Entrainment and oxygen consumption were compared between the protocols for the last 4-min segments for each workload. These comparisons showed that the presence of the auditory cue significantly increased entrainment from 29 to 74%, but oxygen consumption was not significantly changed.Key words: breathing pattern, entrainment, exercise, locomotor-respiratory coupling, ventilation